package 栈和队列;

public interface Queue {
    //返回队列的大小
        public int getSize();
        //判断队列是否为空
        public boolean isEmpty();
        //数据元素 e 入队
        public void enqueue(Object e);
        //队首元素出队
        public Object dequeue() throws QueueEmptyException;
        //取队首元素
        public Object peek() throws QueueEmptyException;

}
